Engine-driven compressor unit



Nov. 27, 1962 F. LEHNER 3,065,900

ENGINE-DRIVEN COMPRESSOR UNIT Filed Feb. 11, 1960 4 Sheets-Sheet l II 1| m H 1| 11 1mm H II 1H] M/VE'NTOR FELIX LEI/IVER Nov. 27, 1962 F. LEHNER ENGINE-DRIVEN COMPRESSOR UNIT 4 Sheets-Sheet 2 Filed Feb. 11, 1960 INVEN T FELIX L EHNER Mim Nov. 27, 1962 F. LEHNER 3,065,900

ENGINE-DRIVEN COMPRESSOR UNIT Filed Feb. 11, 1960 4 Sheets-Sheet 3 llvvmrae FEL/X LEHAIFIQ BY M ul In: Arron Y Nov. 27, 1962 F. LEHNER 3,065,900

' ENGINE-DRIVEN COMPRESSOR UNIT Filed Feb. 11, 1960 4 Sheets-Sheet 4 INVENTOR f/x 41. 44.4-

t d States Patent a $9 53 ENGINE-DRIVE COMPRESSOR UNIT Felix Lehne'r, Graz, Austria, assignor in H ns L st, a Aus Filed Feb. 11,1960, Ser. No; 8,152 Claims priority, applicatiouAustriaiApr. 25, 1959 9 Claims. (Cl. 230-56} The present invention relates to an engine-driven. compressor unit, and more particularly to a compressor unit wherein the compressor pistons: are operated by one or more internal combustion engines.

Engine-driven compressor units of presently known design normally utilize a series of horizontal compressor cylinders whose pistons are reciprocated by an engine which is mounted at the, top of the compressors housing and embodies a series of vertical cylinders Whose pistons rotate a crankshaft which latter is; operatively connected with and reciprocates the pistons in the compressor cylinders. Thus, the cylinders of the compressor component are perpendicular to the engine cylinders.

A serious disadvantage of such prior compressor units is that, owing to the provision of a single crankshaft which is rotated by the pistons of the engine and reciprocates the pistons in the compressor cylinders, the speed at which the pistons of the engine operate cannot exceed the speed at which the crankshaft reciprocates the pistons in the compressor cylinders. This is undesirable because,

the compressor unit is to operate with optimum efiiciency, the engine speed should normally exceed the speed at which the pistons in the compressor cylinders reciprocate. All presently known solutions and proposals for the solution of the above outlined problem are unsatisfactory because, in an eifort to increase the efliciency of the compressor component, they suggest to increase the dimensions of the engine component with attendant thermal problems and excessive fuel consumption.

In certain types of the above outlined known compre-s sor units, the pistons in the engine cylinders and in the compressor cylinders act upon the same crank pins, i.e. the connecting rods of an engine piston and of a compressor piston which act upon the same crank pin forming part of a single crankshaft are immediately adjacent to each other. Alternately, one of the adjacent connecting rods is forked to'receive between its prongs thehead of the other connecti'ng'rod. For example, it is known to use forked connecting rods for the pis-tons'in the engine cylinders and to mount the heads of connecting rods for the pistons in the compressor cylinders on the same crank pins between the bifurcated portions of the respective connecting rods for the pistons in the engine cylinders. in such instances, the stroke and the average speed of the'engine pistons and of the compressor pistons are always the same. However, since the compressor cylinders must have a predet'erminedclearance or dead space which imposes limits upon the dimensions of valves accommodated therein, and since the speedat which such valves may operate cannot be increased beyond a given value if the efliciency of-the compressor is to remain at a satisfactory level, the speed at which the pistons of the compres sor cylinders can be operated by an engine-driven crankshaft cannot exceed a predetermined maximum mag nitude. Thus, the maximum permissible speed of the pistons in the compressor cylinders controls the maximum speed of the engine pistons despite the fact that, it such conventional "engine-driven compressor units would permit it, the engine should preferably operate at-rnuch higher speeds, i.e. were the speed at which the pistons in the engine cylinders operate entirely independentof the speed at which the pistons in the compressor cylinders operate, the former wouldbe reciprocated at much higher speeds 3,065,906 Ce Patentecl- Now-.195?

than is now permissible. Therefore, such known oompressor. units preferably compriseengines wherein the.di,- ameter of each cylinder equals I the length. of. its pistons stroke which increases the output of such engines despite their comparatively low speed. A drawback typical of such constructions is in increased thermal stresses upon the cylinder heads and upon the pistons of the engine.

In'order to. avoid the above-enumerated drawbacks of such prior compressor units, itwas already proposed to increase the speed of the pistons in the-engine cylinders by the provision of separate throlwson the common crankshaft for the connecting rods of the pistons in the engine cylinders on the one. hand, and for the connecting rods of the pistons in the compressor cylinders onthe other hand. The. two sets of throws have different crank radii. However, such construction necessitates the} provision of additional webs between the adjacent throws which, in turn, undulylengthens the crankshaft and brings about a highly undesirable increase in internal stresses within the crankshaft. In addition, the spacing between the adjacent connecting rods of the engine pistons and compressor pistons is increased by a distance equal to the thicknesses of additional crank webs, this resulting in proportionally increased spacing between the crankshaft bearings and attendant increases in bending stresses. The detrimental effect of such bending stresses is further increased by the: undesirable distribution of forcesarising in the additionally provided crank throws.

According to a further known proposal, the-connecting rod for a piston in an engine cylinder is immediately adjacent to the connecting rod for a piston in one of the compressor cylinders, but the two connecting rods are mounted onseparate crank pins provided in a common throw of the crankshaft, and the radius of the crank axle for the connecting rod of the compressor piston is smaller than the radius of the crank axle for the connecting rod of the engine piston. Also, the diameters of crank pins for the connecting rods of the pistons in the compression cylinders are greater than the diameters of crankpins for the other connecting rods. This arrangement will produce different speeds for the engine and compressor pistons coupled with a more compact design of the compressor unit because of alesser number of crank throws and with a better distribution of stresses in the common crankshaft. However, even such arrangements possess a number of serious drawback particularly as regardsthe adaptation ofthe units outlines to available space, and also because such units cannot utilize engines with a large ,number of cylinders. Moreover, the engine cannot operate at a high speed since the latterstill depends upon the speed ofthe compressors pistons. Thus, the unit cannot utilize a high-speed multi-cylinder enginewhich is more economical asregards the consumption of fuel, manufacturing costs and many other considerations. In other words, the just described known engine-driven compressor units must be operated by comparatively slow,=l-ar ge, and veryheavy engines whose fuel consumption, in relation to their output, is rather :highand cannot be compared with the output and advantageous :fuel consumption of many recent highespeed multi-cylindeninterneil corn- ;bustion engines.

,Animportant objectof the present invention i's to procompressor component.

.Another object of the inventionis-to provide a compressor-unit of the above outlined characteristics is of very-compact design, which is of lightweight ,and

low-cost construction, which occupies much less space than prior compressor units with the same output and wherein the distribution of stresses is much more favorable than in presently known compressor units.

A further object of the instant invention is to provide a compressor unit of the above described type wherein the compressor component and the engine or driving component may be operated at different speeds, which may be contructed in such a way as to utilize comparatively short and hence much cheaper and more reliable crankshafts, whose lubricating system may be served by a single pumping device and may include a single oil sump, and whose driving component may embody one or more highly versatile, readily serviceable, serially produced multi-cylinder internal combustion engines.

A concomitant object of the present invention is to provide an improved engine-driven multi-cylinder compressor unit which is constructed in such a way that it can .operate at full or at a greatly reduced capacity, wherein certain compressor cylinders may be shut off for inspecdesigned for the same output, and which enables a designer to assemble its components by full consideration of the space available in industrial plants where the improved compressor unit is put to use without in any way reducing the efiiciency of the unit.

With the above objects in view, the invention resides in the provision of an engine-driven multi-cylinder compressor unit which consists of a compressor component and an engine or driving component each including two or more cylinders and at least one crankshaft. The crankshaft or crankshafts of the compressor component are parallel with each crankshaft of the driving component and the latter comprises a crank case which is installed on top of the crank case and within the outline of the compressor component.

The driving connection between the crankshaft means of the driving component and the crankshaft means of the compressor component preferably comprises a pair of meshing gears of different diameters which drive the crankshaft means of the compressor component at a reduced speed, the speed ratio between the speeds of the crankshaft means being usually in the range of between .1:3 and 1:5. Alternately, the driving connection between the crankshaft means of both components may comprise one or more readily releasable coupling assemblies allowing for rapid and convenient disconnection of the elements constituting the driving component from the compressor component.

In this manner, not only the construction but also the layout of the driving component is practically independent from the compressor component which renders it possible to adapt both components to latest technical requirements and to provide a very compact and much cheaper unit since the driving component may consist .of one or more serially produced internal combustion .engines which can be readily detached from the com- .pressor component and utilized for a number of other purposes.

By utilizing 10116 or more serially produced engines, the initial and maintenance costs, as well as the .costs for spare parts of the improved compressor unit are unit are considerably less than the dimensions and weight of 'a comparable apparatus of known design.

According to another feature of the present invention,

the driving component and the compressor component of the improved unit comprise separate crank cases but may be lubricated by a common pumping or lubricant recirculating system. The two components comprise a single oil sump located in the crank case of the compressor component and adapted to collect the lubricant which is recirculated through the engine component. Consequently, the crankshafts of both components may be placed very close to each other so that the compressor unit may utilize a very small and compact gear drive for transmitting rotation from the crankshaft means of the engine component to the crankshaft means of the compressor component. This, in turn, brings about the additional advantage that the overall height of the unit may be reduced which facilitates the lubrication of its component parts. The common lubricant-recirculating pumping system is preferably driven by the crank-shaft means of the engine component and is mounted on the crankcase of the engine.

The cylinders of the compressor component may be arranged in staggered relation at the opposing sides of the latters crankcase to reduce the overall length of the crankshaft means, or the crankshaft means of the compressor component may comprise a series of aligned comparatively short crankshafts each of which may be driven by a separate engine.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of a conventional compressor unit and of four specific embodiments of my improved compressor unit when read in connection with the accompanying drawings, in which:

FIG. 1 is partly front elevational and partly central sectional view of a known engine-driven compressor unit;

FIG. 2 is a top plan view of the compressor unit shown inFIG. 1;

FIG. 3 shows the conventional compressor unit of FIGS. 1 and 2 partly in end elevational and partly in sectional view, the section being taken substantially along the line III-III of FIG. 2, as seen in the direction of arrows;

FIG. 4 is partly front elevational and partly central sectional view of an engine-driven compressor unit embodying my invention, the outline of the conventional compressor unit in the view of FIG. 1 being shown in phantom lines for the sake of comparison;

FIG. 5 is a top plan view of the improved compressor unit of FIG. 4;

FIG. 6 is a partly end elevational and partly sectional view of the unit shown in FIGS. 4 and 5, the section being taken substantially along the line VIVI of FIG. 4, as seen in the direction of arrows, the phantom lines indicating the outline of the conventional compressor unit in the view of FIG. 3;

FIG. 7 is front elevational view of a modified enginedriven compressor unit embodying my invention wherein the phantom lines indicate the outline of the conventional compressor unit in the view of FIG. 1;

FIG. 8 is a top plan view of the compressor unit shown in FIG. 7 but turned through 9'0 degrees, the phantom lines indicating the outline of a conventional compressor unit in the view of FIG. 2;

FIG. 9 is an end elevational view of the compressor unit in the position of FIG. 8;

FIG. 10 is a partly elevational and partly sectional view of a compressor unit which comprises two driving components mounted on the crank case of the compressor component; and

FIG. 11 is a partly elevational and partly sectional view of a compressor unit which comprises two driving components and two compressor components.

Referring first to FIGS. 1 to 3, there is shown an engine-driven multi-cylinder compressor unit of known design which comprises a driving component represented by an internal combustion engine which includes eight serially arranged upright cylinders 2, and a compressor component including four horizontal compressor cylinders 3', all mounted on a common crankcase 1. The crankcase contains a crankshaft 4 which is rotated by the connecting rods 5 connected with the pistons 7, the latter being reciprocably received in the engine cylinders 2. The crankshaft t is'utilized for'operating the nonrepresented pistons in the compressor cylinders 3" by means of a second set of connecting rods 6. The compressor cylinders extend in a horizontal plane from the longitudinal front side of the crankcase 1 whose rear side supports certain apparatus necessary for the operation of the engine, suchas the superchargers 8 of any suitable design. The right hand'end of the crankshaft 4 isconnectedwith a comparatively large flywheel 9. The compressor unit of FIGS. 1 to 3 operates with an output of say 2,060 Hi. and preferably utilizes a gas engine.

Referring now to FIGS. 4 to 6 which illustrate one former my improved engine-driven multi-cylinder compressor unit, the latter again comprises a compressor component including a plurality of horizontal compressor cylinders 3 whose pistons 3a are reciprocated by ahorizontal'crankshaft' l. However, the comparatively large crankcase 1 of the conventional compressor unit shown in FIGS. l to 3 which surrounds certain parts of the cylinders 2 and 3, is replaced in the improved unit of FIGS. 4 to 6 by a much smaller crankcase 1 whose outline merely constitutes a portion of the total outline'of the compressor component. Thetop of the crankcase 1' mounts the crankcase of 21 preferably self-supporting, highispeed, internal combustion en'ginelt) of the V-type. This engine comprises sixteen cylinders 11 arranged in two inclined rows (see FIG. 6). The nonrepresented pistons which are reciprocably received in the engine cylinders 11 and their non-represented connecting rods rotate a second crankshaft 12 which is mounted in the crankcase of the engine it). The axes of crankshafts 4- and 12 are parallel with each other. The driving connection between these crankshafts consists of a comparatively'small spur gear 13 on the crankshaft 12 and a meshingspur gear 14 on the crankshaft 4. The diameter of the gear 14 is much greater than that of the gear 13, i.e. the crankshaft 4 is driven at a fraction of the rotation'al speed of the engine crankshaft 12. Thus, the gears 13, 14 constitute a reducer or step-down gear transmissionwhose speed-reducing ratiomay be varied within any desired range by suitable selection of its parts. The step-downratio is usually in the range of between 1:3 and 1:5, depending upon the desiredoutput of the cornpressercom onent.

An important advantage of the compressor unit shown in FIGS. 4 to 6 is that the gears 13', 14 produce a certain flywheel efiect so that the compressor unit may operate with a much smaller flywheel 15 which is mounted on the rapidly revolvingengine cranckshaft 12. Moreover, with the exception of the oil sump whichis omitted, the engine I0is very similar to a serially produced internal combustion engine of well known design, such as is utilized for-supplying power in many types of industrial plants. It comprises an exhaust-gas turbine 17 operating la. supercharger 16 both mounted at the left-hand end of the engine, i.e. at the end opposite that where the flywheel 15 is mounted.

By way of example, the novel compressor unit of FIGS. 4 to 6 may have the same output, e'.g. 2,000 H.P.-, as the conventional engine-driven compressor unit of FIGS. 1 to 3. However, and as shown in phantom-lines 18, 19 inF1GSn4} 6, respectively, its overall dimensions areconsiderably smaller than those of the known unit in the Views of FIGS; 1 and- 3. This is a very important advantage which not only results in considerable savings in space but also in a greatly reduced material consumption and lower manufacturing cost. The overall weight of the improved compressor unit, too, is reduced considerably. The cost of the unit shown in FIGS. 4 to 6 dosa es may be further reduced if the engine 10 is of the wellknown serially produced type, i.e. if the engine is capable of being'utilized for other purposes. In addition, the designer is free to elect the layout of the compressor component and/ or of the driving component by full consideration of many factors which cannot be considered in the design of conventional compressor units. Also, the output and efiiciency of components of, which the improved compressor unit consists may be varied within any desired range so as to adapt the unit to recent technical requirements and to insure low fuel consumption while the output and efficiency. remain high.

, The lubricant for the engine 10 and for the compressor component of the unit shown in FIGS. 4 to 6 is collected in the oil sump'Zt of the crank case 1 for the compressor crankshaft 4. Thence, the lubricant is recirculated by a gear pump 22 which is connected with the sump 20 in the crank case 1' by a dipor immersion tube 21 and returns the lubricant through suitable filtering and cooling assemblies back into the lubricating system of the engine it) and of the compressor component. Thus, the engine and the compressor component of my improved unit may utilize a common lubricating pump 22 which is preferably mounted on the engine 19 and is driven by the latters crankshaft 12. i

As is best shown in FIGS. 4 and S, the improved compressor unit utilizes a comparatively long crankshaft 4for the connecting rods which operate the pistons 3a in the compressor cylinders 3. The length of this crankshaft cannot be reduced because, owing to certain constructional problems, the cylinders 3 must be spaced a given distance from each other. Thus, the length of the crankshaft 4 normally exceeds the length of the other crankshaft 12 in the V-engine It). A very important advantage of the modified construction of my improved engine-driven multi-cylinder compressor unit which is represented in FIGS. 7 to 9 is that it can operate with a crankshaft for the connecting rods of the pistons in compressor cylinders 3 whose length is reduced to nearly half the length of the crankshaft 4 while the output of the compressor unit may remain the same. This is attained by using a so-called opposed cylinder type compressor component wherein the horizontal compressor cylinders 3 extend in pairs from the front and rear sides of the crank case '1" forming part of the compressor unit, and the cylinders 3 extending from the opposing sides of the crank case 1" are staggered with respect to each other (see FIG; 8). The unit of FIGS. 7 to 9 can utilize a serially produced internal combustion V-engine 10 which is an exact replica of the engine described in connection with the embodiment of FIGS. 4 to 6. Also, the transmission of rotation from the non-represented crankshaft in the crank case of the engine 10 to the non-represented closely adjacent crankshaft of the compressor component preferably occurs in the same manner as in FIGS. 4 to 6, i.e. in a single step by using a pair of meshing speed-reducing gears or the like. The crankshafts of the engine 10 including the cylinders 11 and of the compressor component including the staggered pairs of compressor cylinders 3 are parallel with each other.

The dot-dash lines 18 in FIG. 7 indicate the outline of a conventional engine-driven compressor unit in the view of FIG. 1 It will be readily noted that the compressor unit of FIGS. 7 to 9 occupies much less space than the conventional units with the same output. In FIG. 8, the improved compressor unit is turned through degrees with'respect to the position of FIG. 7, and the phantom lines 23 indicate the outline of a known compressor unit in the, view of FIG. 2. It will be observed that in a plan view, i.e. in a projection onto a horizontal plane, the dimensions of a conventional unit greatly exceed the dimensions of the compressor unit of FlGS. 7 to 9 though the output of both units is substantially the same. The height of the compressor unit with staggered pairs of opposed compressor cylinders is also reduced, as maybe determined by a comparison of FIGS. 3 and 9. In addition, and as already stated hereinbefore, the length of the compressor crankshaft in the unit of FIGS. 7 to 9 is only about one-half the length of the crankshaft 4. A further advantage common to the constructions of FIGS. 4 to 6 and 7 to 9 is that the high stresses developing during the combustion process in the driving component of the compressor unit, i.e. in the cylinders of the engine 10, do not act directly upon the crankshaft of the compressor component and, consequently, the latter may be manufactured in accordance with more economical processes.

In a slight modification of my invention which is shown in FIG. 10, the improved engine-driven compressor unit comprises a pair of serially arranged driving components in the form of two internal combustion engines 10, 10 which are parallel with the axis of the crankshaft 4 in the crank case of the compressor component. The crank case 1 of the compressor unit supports the crank cases of the engines 10, 10 in such a way that their respective crankshafts 12, 12 are aligned with each other and are parallel with the crankshaft 4. The crankshafts 12', 12" are connected by means of a releasable coupling 24 so that the crankshaft 4 may be driven by the engines 10, 10" or by the engine 10' alone.

FIG. 11 illustrates another modification of the invention wherein the crankshaft 4 is replaced by two shorter crankshafts 4, 4" of equal length. Each of these crankshafts is driven by a separate engine 10, 10" respectively. In other words, each of the two engines 10, 10 operates only one half of the total number of compressor cylinders which brings about the advantage that the compressor unit may operate with comparatively short crankshafts. Such arrangement is particularly desirable when the compressor unit must operate at less than full capacity which can be achieved by arresting one of the engines 10, 10" and by operating only the crankshaft 4 or 4 of the one or the other pair of compressor cylinders 3. This results in greatly reduced fuel consumption and renders it possible to carry out repairs in one half of the compressor unit while the other half remains in operation. The driving connection between the crankshafts 12', 4 and 12 and 4", respectively consists of gears 13, 14' and 13", 14". The crankshafts 4, 4 are connected by a releasable coupling 25. When the coupling 25 is inactive, the crankshaft 4 may be driven independently of the crankshaft 4", or vice versa, so that repairs may be carried out in either of the two engines or in either of the two compressors without interrupting the operation of the other engine and of the respective compressor.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A compressor unit comprising, in combination: a compressor component including a crank case, a plurality of cylinder means mounted on and extending in a substantially horizontal plane from said crank case, said cylinder means located at the level of said crank case and the outline of said compressor component corresponding substantially to the projection of said crank case and of said cylinder means onto a horizontal plane, piston means reciprocable in said cylinder means, crankshaft means in said crank case, and connecting rod means connected with said piston means and with said crankshaft means for reciprocating the piston means when said crankshaft means is rotated; and a driving component including at least one internal combustion engine having a crankcase mounted on top of said first mentioned crank case within the outline of said compressor component and crankshaft means parallel with said first mentioned crankshaft means, said last mentioned crankshaft means mounted in the crank case of said driving component, and means operatively connected with both said crankshaft means for rotating the first mentioned crankshaft means at a speed less than the speed of said last mentioned crankshaft means.

2. A compressor unit comprising, in combination: a compressor component including a crank case, a plurality of substantially horizontal cylinder means mounted on and extending from said crank case, said cylinder means located at the level of said crank case and the outline of said compressor component corresponding substantially to the projection of said crank case and of said cylinder means onto a horizontal plane, piston means reciprocably mounted in said cylinder means, crankshaft means mounted in said crank case, and connecting rod means mounted on and movable by said crankshaft means and operatively connected with said piston means for reciprocating the same; and a driving component including at least one internal combustion engine comprising a crank case mounted on top of said first mentioned crank case within the outline of said compressor component, crankshaft means mounted in said last-mentioned crank case and parallel with the first mentioned crankshaft means, cylinder means, piston means reciprocably received in said last mentioned cylinder means, and connecting rod means connected with and movable by said last mentioned piston means and mounted on said last mentioned crankshaft means for rotating the same; a single oil sump for both said crankshaft means, said oil sump provided in said first mentioned crank case; and a driving connection between said last mentioned crankshaft means and said first mentioned crankshaft means for rotating the latter at a speed less than the speed of said last mentioned crankshaft means.

3. A compressor unit comprising, in combination: a compressor component comprising a crank case, a plurality of substantially horizontal cylinders mounted on and extending from said crank case, said cylinders located at the level of said crank case and the outline of said compressor component corresponding to the projection of said crank case and of said cylinders onto a hori- Zontal plane, a piston reciprocably received in each cylinder, a crankshaft in said crank case, and a connecting rod for each piston, each connecting rod mounted on and movable by said crankshaft and operatively connected with the respective piston for reciprocating the same; a driving component including at least one internal combustion engine comprising a crank case mounted on top of said first mentioned crank case within the outline of said compressor component, a crankshaft mounted in said last mentioned crank case and parallel with the first mentioned crankshaft, a plurality of cylinders mounted on the last mentioned crank case, a piston reciprocably mounted in each said last mentioned cylinder, a connecting rod for each said last mentioned piston, each last mentioned connecting rod connected with and movable by the respective last mentioned piston and mounted on said last mentioned crankshaft for rotating the same; and a driving connection between said last mentioned crankshaft and the crankshaft of said compressor component for rotating the latter at a speed less than the speed of said last mentioned crankshaft; a single oil sump for both said crankshafts, said oil sump located in said first mentioned crank case; and a single pumping device for recirculating a lubricant from said oil sump into said components.

4. A compressor unit comprising, in combination: a compressor component comprising a crank case, a plurality of substantially horizontal cylinders mounted on and extending from said crank case, said cylinders located at the level of said crank case and the outline of said compressor component corresponding to the projection r, 9 of aid crank case, and of said cylinders onto a horizontal plane, a piston reciprocab'ly received in each cylinder, at least one crankshaft insaid crank case, and a connecting rod for each piston, each connecting rod mounted on and movable by said crankshaft arid operatively connect'ed with the respective piston for reciprocating the same; a driving component including at least one internal combustion engine comprising a crank case mounted on top of said first mentioned crank case within the outline of said compressor component, a crankshaft mounted in said last mentioned crank case and parallel with the first mentioned crankshaft, a plurality of cylinders mounted on the last mentioned crank case, a piston reciprocably mounted in each said last mentioned cylinder, a connecting rod for each said last mentioned piston, each last mentioned connecting rod connected with and movable by the respective last mentioned piston and mounted on said last mentioned crankshaft for rotating the same; and a driving connection between said last mentioned crankshaft and the crankshaft of said compressor component for rotating the latter at a speed less than the speed of said last mentioned crankshaft; a single oil sump for said crankshafts, said oil sump located in said first mentioned crank case; and a single pumping device for recirculating a lubricant from said oil sump into said components, said pumping device mounted on the crank case of said driving component and driven by saidlast mentioned crankshaft.

5. A compressor unit comprising, in combination: a compressor component including a crank case, a plurality of substantially horizontal cylinder means mounted on and extending from said crank case, said cylinder means located at the level of said crank case and the outline of said compressor component corresponding substantially to the projection of said crank case and of said cylinder means onto a horizontal plane, piston means reciprocable in said cylinder means, crankshaft means in said crank case, and connecting rod means connected with said piston means and with said crankshaft means for reciprocating the piston means when said crankshaft means is rotated; and a driving component comprising a pair of serially arranged multi-cylinder engines each having a crank case mounted on top of said first mentioned crank case within the outline of said compressor component, a crankshaft parallel with the crankshaft means of said compressor component and mounted in the crank case of the respective engine, coupling means for releasably connecting the crankshafts of said engines with each other, and means for divingly connecting the crankshafts of said engines with the crankshaft means of said compressor component so as to rotate the crankshaft means of said compressor component at a speed less than the speed of said engine crankshafts.

6. A compressor unit comprising, in combination: a compressor component including a crank case, a first and a second group of substantially horizontal cylinder means mounted on and extending from said crank case, said cylinder means located at the level of said crank case and the outline of said compressor component corresponding substantially to the projection of said crank case and of said cylinder means onto a horizontal plane, piston means reciprocable in said cylinder means, a first and a second crankshaft in said crank case, said crankshafts being aligned with each other, first connecting rod means connected with the piston means in said first group of cylinder means and with the first crankshaft for reciprocating the respective piston means when the first crankshaft rotates, and second connecting rod means connected with the piston means in said second group of cylinder means and with the second crankshaft for reciprocatin the respective piston means when the second crankshaft is rotated; and a driving component comprising a first engine for rotating the first crankshaft and a second engine for rotating the second crankshaft, each of said engines comprising a crank case mounted on top of said first mentioned crank case within the otitline of said compressor componentand a crankshaft parallel with's'aid firstmem tioned crankshafts and mounted in thecra'nk case of the respective engine, and driving connections between the crankshaft of the first engine and said first crankshaft and the crankshaft of the second engine and said second crankshaft for rotating said first and second crankshafts at a speed less than the speed of the respectiveengine crankshafts.

7. A compressor unit comprising, in combination: a compressor component including a crank case, a plurality of parallel substantially horizontal cylinders disposed in two groups mounted on and extending from the opposing sides of the said crank case, said cylinders located at the level of said crank case and the outline of said compressor component corresponding substantially to the projection of said crank case and of said cylinders onto a horizontal plane, a piston reciprocably received in each cylinder, a crankshaft in said crank case, and a connecting rod for each piston, each connecting rod connected with the respective piston for reciprocating the same and mounted on said crankshaft for receiving motion therefrom when the crankshaft is rotated; and at least one engine for rotating said crankshaft, said engine comprising a crank case mounted on top of said first mentioned crank case within the outline of said compressor componeat and a crankshaft parallel with said first mentioned crankshaft and mounted in said last mentioned crank case, and a driving connection for transmitting rotation fromthe engine crankshaft to the crankshaft of said compressor component in such a manner that the latter rotates at a speed less than the speed of said engine crankshaft.

8. A compressor unit comprising, in combination: a compressor component including a crank case, a plurality of substantially horizontal cylinder means mounted on and extending from said crank case, said cylinder means located at the level of said crank case and the outline of said compressor component corresponding substantially to the projection of said crank case and of said cylinder means onto a horizontal plane, piston means reciprocable in said cylinder means, crankshaft means in said crank case, and connecting rod means connected with said piston means and with said crankshaft means for reciprocating the piston means when said crankshaft means is rotated; and a driving component including at least one internal combustion engine comprising a crank case mounted on top of said first mentioned crank case Within the outline of said compressor component, crankshaft means parallel with said first mentioned crankshaft means and mounted in said last mentioned crank case, flywheel means mounted on said last mentioned crankshaft means, and means operatively connected with both said crankshaft means for rotating the first mentioned crankshaft means at a speed less than the speed of aid last mentioned crankshaft means.

9. A compressor unit comprising, in combination: a compressor component including a crank case, a plurality of parallel substantially horizontal cylinders disposed in two groups mounted on and extending in staggered relationship with respect to each other from the opposing sides of said crank case, said cylinders located at the level of said crank case and the outline of said compressor component corresponding substantially to the projection of said crank case and of said cylinders onto a horizontal plane, a pistonreciprocably received in each cylinder, a crankshaft in said crank case, and a connecting rod for each piston, each connecting rod connected with the respective piston for reciprocating the same and mounted on said crankshaft for receiving motion therefrom when the crankshaft is rotated; and at least one engine for rotating said crankshaft, said engine comprising a crank case mounted on top of said first mentioned crank case within the outline of said compressor component and a crankshaft parallel with said first mentioned crankshaft and mounted in said last mentioned 1 1 crank case, and a driving connection for transmitting rotation from the engine crankshaft to the crankshaft of said compressor component in such a manner that the latter rotates at a speed less than the speed of said engine crankshaft. V V

- References Cited in the file of this patent UNITED STATES PATENTS 1,608,528 Raymond Nov. 30, 1926 12 Melcher Dec. 28, 1937 Waseige Nov. 28, 1944 Lamberton Mar. 14, 1950 FOREIGN PATENTS Italy June 3, 1941 

